Transistor-Transistor Logic (TTL)
TTL consumes more power than CMOS logic, but used to be faster. TTL was largely relegated to glue logic applications, such as fast bus drivers on a motherboard. For instance, CMOS technology developed to a point that made it possible to economically integrate much more complex circuits on a single chip than with TTL technology. The final blow came in the mid 1990s when the long-time standard supply of 5V could no longer be maintained for reasons of energy efficiency and to accommodate new generations of high performance CMOS circuits.
The first logic devices designed from bipolar transistors were referred to as standard TTL. The addition of Schottky diodes to the base collector of bipolar transistor was called Schottky logic (S-TTL). Schottky diodes shorten propagation delays within TTL by preventing the collector from going into what is called 'deep saturation." Other Transistor-transistor logic technologies include low-power Schottky (LS-TTL), advanced Schottky (AS-TTL), advanced low-power Schottky (ALS-TTL), and low-voltage TTL (LVTTL).
tecnología TTL se caracteriza por tener tres etapas, siendo la primera la que le nombra:
Puerta NAND en tecnología TTL estándar (N)